TA6 irons are made from 17-4 stainless steel. This is the same type of steel that is frequently used in the aerospace industry and in precision surgical instruments. It ranks quite high in strength and will not corrode.
TA6 irons are designed to offer optimal performance for most golfers by removing material from the cavity and relocating it to the sole and perimeter. By creating a wider sole, the center of gravity has been moved lower and further away from the clubface making it easier to get the ball in the air quickly. The added weight around the club's perimeter also helps to keep the face from twisting when the ball is struck off-center.